Hoisting mechanism for cranes.



H. SAWYER.

HOISTING MECHANISM FOR CRANE-S.

APPLICATION FILED JUNE 8, 1909.

Patented Dec. 21, 1909.

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HARRY SAWYER, OF MUSKEGON, MICHIGAN.

I-IOISTING MECHANISM FOR CRANES.

Specification of Letters Patent.

Patented Dec. 21, 1909.

1909. Serial No. 500,876.

To all whom it may concern:

Be it known that I, I'IARRY SAWYER, a citizen of the United States,residing at Muskegon, county of Muskegon, and State of Michigan, havemade a certain new and useful Invention in Hoisting Mechanism forCranes, of which the following is a specification.

This invention relates to hoisting mechanism for cranes and otherurposes, and particularly in the matter of reaving the hoisting andsafety ropes and cables employed.

The object of the invention is to provide an arrangement of hoistingcables for apparatus of this nature, and auxiliary or safety cablesassociated therewith, and in such relation as to enable the load to becarried by either one or the other of said cables, or by both.

A further object of the invention is to provide an arrangement ofhoisting cable, and auxiliary safety cable designed to take the load incase the hoisting cable should part or give way.

Other objects of the invention will appear more fully hereinafter.

The invention consists substantially in the construction, combination,location and arrangement of parts, all as will be more fully hereinafterset forth, as shown in the accompanying drawing, and finally pointed outin the appended claims.

Referring to the accompanying drawing,

and to the various views and reference signs appearing thereon, Figure1, is a view in side elevation of a hoisting mechanism showing thearrangement of main and auxiliary or safety cables embodying theprinciples of my invention. Fig. 2 is an end elevation of the same. Fig.3 is a detached detailed View in perspective of a rocking arm employedin connection with my invention.

The same part is designated by the same reference sign wherever itoccurs throughout the several views.

In the practical operation of hoisting cranes and similar apparatus, itis desirable to supplement the main hoisting cable with an auxiliarycable designed to act as a safety device in case the main cable shouldbreak, and it may be sometimes desirable to so arrange the main andauxiliary or safety cables as to enable the load to be transferred fromthe one to the other, or to be distributed bet tween them. It is alsodesirable to provide for the stretching of the hoisting cables, and toequalize between the main and safety cables in case of stretching of theone or the other. It is among the special purposes of my presentinvention to provide a construction and arrangement of cables whichaccomplishes this and other advantages.

In carrying out my invention I employ the main cable A, and theauxiliary cable B, the former being shown shaded to indicate the strandsof which it is made and the latter being shown without such shading soas to readily distinguish them in the drawings. These cables are woundupon the hoisting drum 0, which may be of any suitable or convenientconstruction and arrangement according to the purposes and objects ofthe apparatus in connection with which the hoisting mechanism isemployed. In practice I prefer to wind the two cables in alternaterelation upon the drum as most clearly indicated in Fig. 1.

In the framework carrying the hoisting drum, or in any other suitable orconvenient relation are pulleys D and E.

Reference signs F, G, designate pulleys carried in a frame H, designedto receive the load to be hoisted. The main hoisting cable A extendsover the drum C, down to and the pulleys D, thence down again aroundanother one of the pulleys F, thence up around a small pulley J, carriedin the end of a lever K, thence horizontally to and around a smallpulley L, carried in the end of another lever P, thence down and aroundone of the pulleys G, thence up over another pulley D, thence down andaround another pulley G, and thence back to the drum. The auxiliary orsafety cable extends from the drum C, down and around one of the pulleysF, thence up and around pulley E, thence again down and around a pulleyF, and thence up and around a small pulley M, carried in the upper endof lever K, thence downwardly and around a small pulley inclicatcd at N,yieldingly mounted as hereinafter more fully described, thence upwardlyand around a small pulley 0, carried in the upper end of the lever P,thence down and around a pulley G, up and around another pulley E,thence again down and around a pulley G, and thence back to the hoistingdrum C. The levers K, and P, are mounted to freely rock upon the shaftsor axles cararound one of the pulleys F, thence up over i rying thepulleys D, and E, or mounted to rock in any other suitable or convenientmanner as may be desired. The relative inclinations of the levers K, andP, maybe adjusted in any suitable or convenient manner, and in eitherdirection. As illustrative of one form of arrangement for accomplishingthis result, but to which my invention, as defined in the claims is notto be limited or restricted, I have shown the levers K, P, provided withprojections R, cooperating with adjustable limit stops S, by means ofwhich the relative angularity of said levers, and the amount of movementthereof, may be adjusted and limited as desired. The small pulley N, iscarried upon a bolt T, having a collar V, against which operates aspring W, whereby said pulley may move against the action of saidspring. Through suitable nuts U, the tension of the spring WV, may beadjusted.

By the arrangement and construction above described, it is obvious thatthe entire hoisting strains or load may be readily transferred from oneto the other of the cables by merely rocking the levers K, P, in onedirection or the other, or divided uniformly between the cables byallowing the levers a limited amount of free movement. It will beobserved that said levers are so relatively positioned in angularrelation as to bring their upper ends toward each other, and to separatetheir lower ends. Therefore, since one of the cables operates over thepulleys J, L, in the lower ends of said levers while the other cableoperates over pulleys M, 0, carried in the upper ends of said levers, itis merely necessary in order to transfer the load from one to the otherof the cables, or to distribute the load between them, to relativelyadjust the relative angularity between said levers, this adjustmentbeing effected by the adjusting limit screws S. Thus by turning up onthe outer screws S, the upper ends of the levers K, P, are caused toapproach each other thereby paying out auxiliary cable B, or lengtheningthe bights of said cable. The same adjustment of the levers K, P, causesthe lower ends thereof to be separated farther apart, thereby taking upor shortening the bight of the main cable. In this manner all or aportion of the load may be imposed on the main cable. Similarly, byturning up on the inner limit or adjusting screws S, the reverse of theabove described operation will take place, thereby imposing the entireor a part of the load upon the auxiliary cable.

In case for any reason the entire load is suddenly transferred upon theauxiliary cable, such load will first be taken by the spring \V, therebyrelieving the cable of the application thereto of a sudden jerkingstrain. Again, in case the load is carried by the main cable, and saidcable should stretch, and it may not be desired to impose any materialpart of the load on the auxiliary or safetycable, but merely to permitthe auxiliary cable to have just sufficient tension to move easily andfreely, the stretching of the main cable would naturally impose anincreasing strain on the auxiliary cable. To prevent this, theyieldingly mounted pulley N, permits the auxiliary cable to yieldwithout taking an undue portion of the load by reason of the stretchingof the main cable.

lVhile I have shown and described my invention as applied to a hoistingcrane, I do not desire to be limited or restricted in respect to theparticular kind or class of hoisting mechanism in connection with whichmy invention is used.

It is obvious that any desired power mechanism for operating thehoisting drum may be employed, and it is equally obvious that the loadmay be connected to any desired construction or arrangement of hoistingframe to be engaged by the hoisting cables. My invention therefore, asdefined in the claims, is not to be limited or restricted in respect tothese features.

Having now set forth the object and nature of my invention, and aconstruction embodying the principles thereof, and hav ing described thepurpose, function and mode of operation thereof, what I claim as new anduseful and of my own invention and desire to secure by Letters Patentis:

1. In a hoisting mechanism, a main and auxiliary or safety hoistingcable, and means fortransferring at will the load from the one to theother of said cables, and for automatically distributing the loadbetween them.

2. In a hoisting mechanism, a main and an auxiliary safety cable, one ofsaid cables being arranged to take a hoisting load, and the other tonormally run idle, in combination with means for transferring the loadfrom the one to the other of said cables, and to automaticallydistribute the load between them.

3. In a hoisting mechanism, a main and an auxiliary safety cable, one ofsaid cables being arranged to take the hoisting load, and the other toremain idle, in combination with a yielding connection for the idlecable whereby said cable is relieved of any in crease in load by reasonof the stretching of the load carrying cable.

4. In a hoisting mechanism, a main and an auxiliary safety cable,pulleys over which said cables respectively operate, levers car- 7 ryingsaid pulleys at the respective ends thereof, and means for adjustablyrocking said levers.

5, In a hoisting mechanism, a main and an auxiliary hoisting cable,pulleys over which said cables respectively operate, angularly arrangedlevers carrying said pulleys at the respective ends thereof, and meansfor adjusting the angular relations of said levers with reference toeach other.

6. In a hoisting mechanism, a main and an auxiliary hoisting cable,relatively movable pulleys over Which said cables respectively operate,means for relatively moving said pulleys, and a yielding connection forone of said cables.

7. In a hoistin mechanism, a main and an auxiliary safety cable, pulleysover which said cables respectively operate, angularly arranged leverscarrying said pulleys, arms connected to said levers, and adjusting 5screws for engaging said arms to rock said levers.

In testimony whereof I have hereunto set my hand in the presence of thesubscribing Witnesses, on this 4th day of June A. D., 2

HARRY SAVVYER. Witnesses J. L. HAGA, T. C. AKIN,

P. J. KNIPERs.

